Charging plug and charging plug/charging socket system for charging an electric vehicle

ABSTRACT

The present disclosure relates to a charging plug for transmitting a charging current to an electrically operable vehicle, having multiple contact elements for electrically contacting the charging plug with contact elements of a charging socket. According to the present disclosure, the charging plug has a conical or cylindrical plug body, on the outer face of which multiple contact paths that run concentrically about the plug body are formed in a distributed manner in the axial direction. The present disclosure additionally relates to a charging plug/charging socket system comprising such a charging plug and a charging socket with a hollow socket body into which the plug body of the charging plug can be inserted, wherein contact surfaces which run concentrically in the socket body are formed on the inner face of the socket body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 371 to the International Application No. PCT/EP2018/068116, filed Jul. 4, 2018, and to the German Application No. 10 2017 115 224.5, filed Jul. 7, 2017, now pending, the contents of which are hereby incorporated by reference.

DESCRIPTION

The present disclosure relates to a charging plug in accordance with the preamble of claim 1, having multiple contact elements for making electrical contact between the charging plug and contact elements of a charging socket. The present disclosure further relates to a charging plug/charging socket system, having such a charging plug and a charging socket into which the charging plug is insertable in positively locking fashion to make an electrical contact between contact elements of the charging plug and contact elements of the charging socket.

Charging plugs for electrically drivable vehicles are known from the prior art that are molded for connection to a corresponding socket. Such plug/socket connections may be embodied in different ways and for example also comprise introduction aids, locking mechanisms or other supplementary features. The electrical contact between the lines of a charging cable and a corresponding charging component of a vehicle is typically made by multiple contact elements, with attempts being made to standardize the shape and arrangement thereof. In this way, a standardized plug system is supposed to be provided. It is thus commonplace for multiple contact pins to be used as contact elements for an electrical contact between plug and socket, said contact pins being pushed into corresponding contact openings. The contact elements fundamentally need to be dimensioned such that they can transfer sufficiently large charging currents. The contact area of a contact element needs to be designed to be so much larger, the larger the charging current to be transferred.

To produce rapid charging of an electric vehicle via a plug/socket connection of this kind, high charging currents need to be used. Scaling of the dimensions of the contact pins and contact sockets cannot be performed without restriction, however, since this results in a disadvantageous installation space increase and hence in larger plugs. Not only are these heavy and unwieldy, they also increase the costs of a charging station. There is therefore a need to transfer the highest possible charging currents using plug/socket systems having the smallest possible dimensions.

When an energy store of a motor vehicle is charged, the charging plug, which is in the form of a power plug contact, furthermore heats up. The heating of the plug contact should be limited to a specific temperature increase. In order to keep to a limited temperature increase of this kind, the plug connector geometries, which are standardized in the main, only allow the use of charging currents at a level that does not allow rapid charging of a vehicle, however. To solve this problem, for example DE 10 2015 100 347 A1 discloses an electrical connecting body that has a cooling fluid duct for cooling the connecting body with a cooling fluid.

Since the acceptance and spread of electric vehicles is also dependent on the charging time, there is thus a need for charging systems that allow the fastest charging possible without increasing the standardized dimensions. The object of the present disclosure is thus to provide a charging plug/charging socket system that allows increased charging currents even with small plug dimensions.

According to the present disclosure, this object is achieved by a charging plug in accordance with independent claim 1. Advantageous developments of the charging plug emerge from the subclaims 2-6. The object is further achieved by an associated charging plug/charging socket system in accordance with claim 7. Advantageous developments of the charging plug/charging socket system emerge from subclaims 8-10.

It should be pointed out that the features individually listed in the claims can be combined with one another in any technically meaningful manner and demonstrate further configurations of the present disclosure. The description characterizes and specifies the present disclosure additionally, in particular in association with the figures.

The charging plug according to the present disclosure can be used to transfer a charging current to an electrically operable vehicle. The charging plug in this case may be formed on the vehicle or on a charging cable to which the vehicle is connected during charging. The charging plug has multiple contact elements for making electrical contact between the charging plug and contact elements of a matching charging socket. Depending on the embodiment of the charging cable and the vehicle, this charging socket is likewise formed on the vehicle or on the charging cable.

According to the present disclosure, the charging plug has a conical or cylindrical plug body, on the outside of which are formed multiple contact tracks running concentrically around the plug body in a manner distributed in the axial direction.

The contact tracks are situated around the plug body like rings. These contact tracks can be used to make electrical contact with appropriately shaped contacts of a charging socket. The plug body of the charging plug can be of conical or cylindrical shape. A receptacle on an associated charging socket matches this shape of the plug body so that the plug body can be inserted into this receptacle with the precisest possible fit. The charging socket for its part has inner contact elements or contact areas that make electrical contact with the outer contact tracks of the plug body when the charging plug and the charging socket are connected.

The present disclosure therefore turns away from conventional charging plugs having multiple contact pins that are pushed into openings in a charging socket in order to make contact with contacts of the charging socket there. In order to increase the transferrable charging current for rapid charging, the diameter of such contact pins would need to be increased to the extent that the dimensions of the charging plug would disadvantageously increase. The present disclosure instead uses large-area contact tracks on the outside of a plug body. In this way, the contact area between contact elements of the plug and the socket can be advantageously increased, in particular even doubled, for the same plug size.

Further, the arrangement of contact tracks on the outside of a plug body has the advantage that the inside of the plug body can be used for other functions. To this end, the plug body of the charging plug can have for example a cavity running axially through the plug body that can be used to accommodate further functional components. In one embodiment of the present disclosure, a cooling device for conducting a cooling medium through the charging plug passes through such a cavity. This cooling device can comprise not only feed and return connections for the cooling medium but also one or more valves. By way of example, a double ball valve can be used for the flow control of the cooling medium.

In one embodiment of the present disclosure, there is provision for such valve means in the charging plug to serve merely to return the cooling medium from a supply hose back to the charging cable. In this way, the heating of the charging plug can be kept within prescribed limits even during rapid charging. In another embodiment, there is provision for cooling medium also to be able to be provided to the electric vehicle when necessary in order to cool lines and in particular an energy store inside the vehicle. The valve means in the charging plug are then in a form such that they can carry a cooling medium either back to the charging cable or to a vehicle. The coolant is then carried to a vehicle through the charging plug and the charging socket of a vehicle. After passing through the applicable components of the vehicle, the heated cooling medium is carried back through the charging socket of the vehicle to the charging plug and the charging cable.

Connecting the cooling circuit of the charging cable to a vehicle is important in particular for rapid charging. However, use of vehicle cooling can also be advantageous when vehicles are in the sun or an underground garage, since the vehicles cannot release additional charging heat to the outside in these situations. As an alternative to cooling the vehicle, the charging column could also lower the charging power, however.

Whether the vehicle is supposed to be supplied with a cooling medium via the charging cable during charging is preferably decided by a control unit of the vehicle. If the vehicle has no devices for cooling energy stores, for example, the valve means of the charging plug would carry the cooling medium only through the charging plug and back through the charging cable as standard. If a vehicle has the opportunity for cooling, on the other hand, it can request this when necessary. This is effected by means of a control unit of the vehicle. In one embodiment of the present disclosure, the valve means of the charging plug are actuatable by a control unit of the vehicle via a communication connection, for example. In particular, the valve means of the charging plug are actuable via a push rod in this case.

The arrangement of contact tracks on the outside of the plug body of a charging plug therefore has various advantages. Besides the possible increase in the contact area for electrical contacts, the present disclosure also allows the advantageous accommodation of components of a cooling system inside the charging plug. The front of the charging plug may be able to be used entirely for the function of the cooling system in this case. There can, however, also be provision on the front for individual contacts for control lines at low voltage, since these do not require increased contact areas. There are then only the current contacts for the charging on the outside of the plug body.

In order to protect the outer contact tracks on the charging plug from damage and/or soiling and to protect people from contact with the contacts, there is preferably provision for a protective apparatus. By way of example, the charging plug has a cover that covers the contact tracks from the outside, wherein the cover is embodied so as to move in relation to the plug body. The cover can thus adopt an “open” position, in which the contact tracks are exposed, and a “closed” position, in which the contacts tracks are covered in a protective capacity. In a simple form of the present disclosure, the cover can be removed before the charging plug is inserted into a charging socket, and can be mounted on the charging plug again after charging. It is therefore a type of lid or protective sleeve. This is associated with considerable manual effort, however, and there is the risk of loss of the cover.

Greater advantage has thus been found in embodiments in which a cover is mounted displaceably on the charging plug, so that the cover can be moved out of the region of the contact tracks for charging. After charging, the cover is moved back into its protective position. By way of example, in the case of a charging plug with a cylindrical plug body, a cover can be formed by a hollow cylindrical protective tube mounted on the plug body so as to move coaxially in the region of the contact tracks.

In one embodiment of the present disclosure, a protective tube of this kind has, on its inside, an internal thread that is in engagement with an external thread on the plug body. By means of the threaded connection thus formed, the protective tube is mounted so as to be rotatable in relation to the plug body. The protective tube can be rotated, and thus moved axially, on the external thread of the plug body when driven manually or by motor. There is provision for a motor drive on the charging plug itself or on an associated charging socket.

The present disclosure also comprises a charging plug/charging socket system, having a charging plug according to one embodiment of the present disclosure and a charging socket in which the charging plug is insertable in positively locking fashion in order to make an electrical contact between contact elements of the charging plug and contact elements of the charging socket. In this case, the charging socket has a hollow socket body into which the plug body of the charging plug is insertable, wherein contact areas running concentrically in the socket body are formed on the inside of the socket body. These contact areas can likewise be annular contact tracks. In another embodiment of the present disclosure, spanning contacts are used that use a servomotor to bring contact areas into contact with the external contact tracks of the charging plug using the elbow lever principle. The contact tracks of the charging plug are then encompassed by the contact tracks of the charging socket, each contact track of the charging socket encompassing one contact track of the charging plug.

In order to move the described cover of the charging plug covering the contact tracks of the charging plug on the outside, the charging plug/charging socket system in one embodiment comprises drive means for moving said cover. By way of example, the charging socket has a servomotor for moving a cover of the charging plug. The servomotor drives a gripper by means of which the cover is gripped and moved. In one embodiment of the present disclosure, such a servomotor is used not just for moving the cover but also for pulling the charging plug into the charging socket. The drive means then engage the cover such that they pull the charging plug into the charging socket when the cover moves away from the charging socket. This movement of the cover results not only in the contact tracks of the plug body being released but also in the charging plug being pulled into the charging socket as it were. This has the advantage that the charging plug and the charging socket are securely connected to one another.

Furthermore advantages, special features and expedient developments of the present disclosure emerge from the subclaims and the description of preferred exemplary embodiments below with reference to the figures, in which:

FIG. 1 shows a schematic front view of the connecting side of a charging plug from the prior art;

FIG. 2 shows a schematic longitudinal section through a charging plug as shown in FIG. 1;

FIG. 3 shows a schematic front view of an embodiment of a charging plug according to the present disclosure;

FIG. 4 shows a schematic side view of a charging plug as shown in FIG. 3 with the cover closed;

FIG. 5 shows a schematic side view of a charging socket;

FIG. 6 shows a schematic side view of a charging plug as shown in FIG. 3 with the cover open; and

FIG. 7 shows a connected charging plug/charging socket system.

The charging plug according to the present disclosure is preferably part of a charging cable that is attached to a charging station for electrically operable vehicles. The charging station is connected to an energy source, from which current is transferrable to a vehicle via the charging cable. To this end, the charging cable is temporarily connected to the vehicle, this being done by means of an appropriate plug/socket connection. This usually involves the use of plug/socket connections as are depicted in exemplary fashion in FIGS. 1 and 2. FIG. 1 shows a front view of a charging plug 60, the connecting side of which has contacts formed on it for various single lines. The connecting body to be connected on the vehicle has corresponding contacts that are brought into electrical contact when the two components are connected. In the embodiment of FIG. 1, there is provision for multiple power lines for the charging current L1, L2, L3, a neutral line N and a protective line PE, for example. Further, there is in the charging cable a pilot signal line CP (control pilot) for transferring pilot signals and what is known as a plug present line (PP), by means of which an electric vehicle can indicate a charging station whether or not a charging cable having a plug is plugged in.

In order to make contact with these lines L1, L2, L3, N. PE, CP and PP, there is provision for multiple contact pins 71, 72, 73 on an associated charging socket 70 (FIG. 2). Contact pins 71 for control lines CP and PP have a smaller diameter than contact pins 72, 73 for the other lines L1, L2, L3, N and PE. These contact pins 71, 72, 73 of the charging plug 70 are pushed into corresponding openings in the charging socket 60 in order to make an electrical contact there.

The present disclosure turns away from such known plug/socket systems having the known problems and instead provides a charging plug as shown in FIGS. 3 and 4. Fundamentally, the figures show the features relevant to the present disclosure only schematically in this case. It is clear to a person skilled in the art that these features can be complemented by known features such as housings, guides, locking mechanisms, etc. In this instance, FIG. 3 shows a plan view of the charging plug 10 in FIG. 4 from above. The charging plug 10 has a cylindrical plug body 11 that is preferably shaped as a hollow cylinder and therefore has a cavity 14. This cavity 14 can accommodate components of a cooling system (not depicted).

On the outside of the plug body 11, there is provision for multiple concentrically running contact tracks 30, 31, 32, 33 and 34 arranged beside one another in the axial direction. These contact tracks are depicted only schematically in FIG. 4 and are insulated from one another. The contact tracks are furthermore connected to lines of a charging cable, which can be lines L1, L2, L3, N, PE, CP and PP as in the case of known charging plugs. In the embodiment of FIG. 4, there are merely five contact tracks formed on the outside of the plug body 11 for the lines L1, L2, L3, N and PE. Circular contact tracks for the control lines CP and PP are formed on the front of the plug body 11, however. These are depicted in FIG. 3 by concentric black circles of greater thickness.

In one region of the plug body 11, there is furthermore an external thread 41 formed. A protective tube 12 having a corresponding internal thread 40 is screwed onto this external thread 41. FIG. 4 shows the protective tube 12 in the closed position, in which it conceals the contact tracks 30, 31, 32, 33 and 34 and thus shields them against contact from the outside. Part of the thread 41 and of the plug body 11 are accommodated in a housing 13, from which the plug body 11 with the contact tracks 30, 31, 32, 33 and 34 protrudes.

The protective tube 12 can be rotated or pushed into an open position by a servomotor, not depicted. FIG. 6 conveys this process by means of two arrows in the direction of the housing 13. The servomotor rotates the protective tube 12 on the external thread 41, so that it is pushed in the direction of the housing 13 and thus releases the contact tracks 30, 31, 32, 33 and 34. A charging socket 20, as can be inferred from the schematic depiction of FIG. 5, can then be pushed over the plug body 11 of the charging plug 10. To this end, the charging socket 20 essentially has a hollow cylindrical socket body 21, on the inside of which multiple contacts are arranged. These contacts are depicted in simplified fashion in FIG. 5 as annular contact tracks 50, 51, 52, 53. Preferably, spanning contacts are used that, by means of a servomotor, can bring contact areas into contact with the external contact tracks of the charging plug 10 using the elbow lever principle. The contact tracks 30, 31, 32, 33 of the charging plug 10 are then encompassed by the contact tracks 50, 51, 52, 53 of the charging socket 20, each contact track of the charging socket encompassing one contact track of the charging plug. FIG. 7 shows a charging socket 20 after having been pushed onto the charging plug 10. 

1. A charging plug for transferring a charging current to an electrically operable vehicle, having multiple contact elements for making electrical contact between the charging plug and contact elements of a charging socket; wherein the charging plug has a conical or cylindrical plug body, on the outside of which are formed multiple contact tracks running concentrically around the plug body in a manner distributed in the axial direction.
 2. The charging plug of claim 1, wherein the charging plug has a cover that covers the contact tracks from the outside, wherein the cover is embodied so as to move in relation to the plug body.
 3. The charging plug of claim 2, wherein the charging plug has a cylindrical plug body and the cover is a hollow cylindrical protective tube mounted on the plug body so as to move coaxially in the region of the contact.
 4. The charging plug of claim 3, wherein an internal thread is formed on the inside of the protective tube, which internal thread is in engagement with an external thread on the plug body, and the protective tube is mounted by means of the threaded connection thus formed so as to be rotatable in relation to the plug body.
 5. The charging plug of claim 1, wherein the plug body of the charging plug has a cavity running axially through the plug body.
 6. The charging plug of claim 1, wherein a cooling device for conducting a cooling medium through the charging plug runs into the cavity.
 7. A charging plug/charging socket system, having the charging plug of claim 1 and a charging socket in which the charging plug is insertable in positively locking fashion in order to make an electrical contact between contact elements of the charging plug and contact elements of the charging socket; wherein the charging socket has a hollow socket body into which the plug body of the charging plug is insertable, wherein contact areas running concentrically in the socket body are formed on the inside of the socket body.
 8. The charging plug/charging socket system of claim 7, further comprising: a drive means for moving a cover of the charging plug that covers the contact tracks of the charging plug from the outside.
 9. The charging plug/charging socket system of claim 8, wherein the charging socket further includes a servomotor for moving a cover of the charging plug.
 10. The charging plug/charging socket system of claim 8, wherein the drive means engages the cover such that it pulls the charging plug into the charging socket when the cover moves away from the charging socket. 